#include<iostream>
#include<vector>
#include<queue>
#include<cstring>
#include<cmath>
#include<map>
#include<set>
#include<cstdio>
#include<algorithm>
#define debug(a) cout<<#a<<"="<<a<<endl;
using namespace std;
const int maxn=1e5+100;
typedef long long LL;
inline LL read(){LL x=0,f=1;char ch=getchar();	while (!isdigit(ch)){if (ch=='-') f=-1;ch=getchar();}while (isdigit(ch)){x=x*10+ch-48;ch=getchar();}
return x*f;}
LL dp[maxn],siz[maxn];
vector<LL>g[maxn];
LL ans[10],tot=0;
void dfs(LL u,LL fa,LL n){
    siz[u]=1;
    for(LL i=0;i<g[u].size();i++){
        LL v=g[u][i];
        if(v==fa) continue;
        dfs(v,u,n);
        siz[u]+=siz[v];
        dp[u]=max(dp[u],siz[v]);
    }
    if(max(dp[u],n-siz[u])<=n/2) ans[++tot]=u;
}
int main(void)
{
  cin.tie(0);std::ios::sync_with_stdio(false);
  LL t;cin>>t;
  while(t--){
    LL n;cin>>n;
    tot=0;
    for(LL i=0;i<n+10;i++) g[i].clear(),dp[i]=0,siz[i]=0;
    for(LL i=1;i<n;i++){
        LL u,v;cin>>u>>v;
        g[u].push_back(v);
        g[v].push_back(u);
    }
    dfs(1,0,n);
    if(1==tot){
        for(auto i:g[ans[tot]]){
            cout<<ans[tot]<<" "<<i<<"\n";
            cout<<ans[tot]<<" "<<i<<"\n";
            break;
        }
    }
    else{
        for(LL i=0;i<g[ans[1]].size();i++){
            LL v=g[ans[1]][i];
        ///    debug(v);
            if(v==ans[2]) continue;
            cout<<ans[1]<<" "<<v<<"\n";
            cout<<ans[2]<<" "<<v<<"\n";
            break;
        }
    }
  }
return 0;
}
